Milltek Rear Silencer Bypass (Non-Valved) with JET-90 Carbon Trims for BMW 125i F20/F21 3 & 5-Door Hatch (B48, 2016+) - Rear Box Delete, Louder Exhaust - Requires M135i Valance

Back Box Delete with 90 mm Carbon Fibre Tailpipes by Milltek for BMW 1 Series 125i F20 F21 B48

Turn up the soundtrack of your 1 Series with Milltek’s axle-back straight section and carbon fibre tailpipe finishers. This rear-end upgrade replaces the factory tail silencer for a deeper, sharper, more purposeful tone, while the twin 90 mm carbon tips deliver a motorsport-inspired look that suits the F20 and F21 hatch perfectly.

Crafted in Britain from high quality T304 stainless steel and expertly TIG-welded, this free-flow rear section is designed for longevity and resistance to corrosion. Precision mandrel bends maintain consistent diameter through the pipework to promote smooth gas flow, giving a clean, performance-led sound character with minimal cabin boom. It is a great choice if you want a consistent fixed-tone setup without electronics or valves.

Why enthusiasts choose this upgrade

• Tailbox removal for a more vocal, engaging soundtrack
• Fixed-tone rear section for a steady, aggressive note at all times
• Twin 90 mm carbon fibre tailpipe finishers for a premium, track-ready aesthetic
• UK-made T304 stainless construction for strength and durability
• Mandrel-bent, free-flow design to reduce restriction versus the factory rear muffler
• Engineered sound with minimal boom or unwanted cabin resonance
• OE-style hangers for straightforward fitment

Compatibility

• BMW 1 Series 125i F20 3-door and F21 5-door
• B48 2.0 turbo petrol models
• 2016 onward
• Requires the M135i rear diffuser or valance to suit the larger twin tips

What you can expect

A crisper, sportier tone outside, a cleaner note inside the cabin and a high-end finish that looks as good as it sounds. We run Milltek systems on our own cars and our customers consistently praise the sound quality, precise fit and premium build. If you want a simple, effective sound upgrade for your 125i that looks the part, this is a brilliant solution.

Professional installation

Want it fitted by specialists We can help. Book installation with MJ Modifications in Warwickshire. Request a fitting quote at info@mjmodifications.co.uk.

Helpful searches

BMW 1 Series 125i back box delete, 125i F20 F21 muffler delete, axle-back straight pipe 125i, carbon fibre exhaust tips 90mm BMW 1 Series, twin exit tailpipes 125i, Milltek Sport 1 Series tailpipe upgrade, B48 exhaust sound upgrade, F20 F21 hatchback exhaust rear section, 125i performance tailpipes UK, M135i diffuser required for twin tips, stainless T304 axle-back BMW 125i, non-valved rear section 1 Series, BMW 125i sports exhaust rear end, Milltek carbon tips 90 mm.